This invention relates in general to a method for the decoloring and refining or purifying of beet juice.
More particularly, this invention is concerned with decoloring and refining processes which include the step of more efficiently discoloring and purifying beet juice containing colorants in sugar-manufacturing processes, by the use of adsorbent of similar type of synthetic hydrotalcite, at the temperature of 40.degree.-100.degree. C. or more preferably at 60.degree.-80.degree. C.
Also, in a first embodiment of the invention, the process includes a step for efficiently regenerating an adsorbent by replacing the adsorbate through ion exchange by contacting an adsorbent containing the adsorbate with various inorganic salts-solutions to cause the ion-exchange.
In the second embodiment of the invention, the process includes a step for efficiently regeneration, an adsorbent by removing the adsorbate through heating of the adsorbent within a temperature range as high as 750.degree.-950.degree. C. or preferably 800.degree.-900.degree. C.
Originally, sugar beet as a raw material for manufacturing the sugar does not contain any pigment, however, it is known that colorants are formed in beet juice during the sugar-manufacturing process.
These colorants are various on those types and are chemically unknown on numerous points, and yet, these are generally said to be caramel-substances, polyphenol-iron complexes, melaidine, and melanine.
Accordingly, in order to inhibit the formation of these pigments, hydrogen sulfide, ascorbic acid, sulfurous acid gas, etc., namely, deoxidizers have been used so far, without sufficient results. In the treatment os sugar cane, decoloring, purification or refinement of colored juice is performed by the combined use of activated carbon with organic ion exchange resins. However, in the treatment of beet juice, it is improper to use the activated carbon, and the decoloration is now typically being made by the combined treatment with SO.sub.2 - gas (saturated or blowing-off of the gas), and organic ion exchange resins but, it is not preferable to use such gas in view of food-hygiene.